Field of the Invention
The present invention relates generally to fuel dispensers and, more particularly, to a fuel dispenser having a sensor for determining the removal and replacement of a fuel nozzle within a dispenser receptacle.
Many localities require a two-step activation process for a fuel dispenser because of local fire code regulations. This two-step process is based on standards established by organizations such as Underwriters Laboratories ("UL") or the National Electric Code. UL Standard 87, "Power-Operated Petroleum Dispensing Devices," establishes a requirement that a motor capable of providing fuel to a nozzle not be started simultaneously with the lifting of the hose or nozzle from its rest position on the dispenser. As a practical matter this requirement creates a two-step dispenser activation process whose first step typically is removing a nozzle from a receptacle and whose second step may take a variety of forms.
Presently, fuel dispensers have used a wide variety of techniques to activate the dispensers upon removal of the nozzle. One technique includes a flap assembly mounted within the nozzle receptacle. The flap assembly is within the receptacle such that the nozzle engages the flap assembly when placed into the receptacle. The movement of the flap assembly moves a magnet on the flap assembly out of proximity of a reed switch, thereby opening a circuit and disabling the dispensing of fuel. When the nozzle is removed from the receptacle, the flap assembly moves within proximity of the reed switch to close the circuit and allow dispensing of the fuel. This embodiment is disclosed in U.S. Pat. No. 5,110,010, hereby incorporated by reference in its entirety.
One drawback of this embodiment is the need for mechanical components within the flap assembly including a nozzle flap, springs, magnet, and flap mounting bracket. Repeated activation and deactivation of the flap assembly may cause fatigue to these parts resulting in failure of the flap assembly, especially considering that many of the fuel dispensers are activated hundreds of times each day. Additionally, many of the fuel dispensers are exposed to weather, and dirt and debris from vehicles which can further interfere with the accuracy and reliability.
These mechanical components also add cost to the dispenser. Each nozzle receptacle must be individually equipped with the components to operate effectively. This cost is magnified for dispensers having multiple hoses and receptacles for each grade of fuel.
Thus, there is a need for a more reliable and cost-effective means of activation and deactivating a fuel dispenser.